Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highl...Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highly valuable ester derivatives were obtained in a direct and rapid way.This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance,using cheap and abundant electrodes and completed within a short reaction time.Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology.The mechanistic investigations and density functional theory(DFT)calculations verified the feasibility of the proposed pathway of this transformation.展开更多
The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation....The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation.Considering the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision energies.Remarkably,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain elimination.Chemical dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing processes.Interestingly,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism shift.These features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.展开更多
Ubiquitous competition of stereospecific E2 elimination versus SN2 substitution is of central importance in chemical synthesis.Herein,we uncover how the nature of the leaving group affects the intrinsic competing dyna...Ubiquitous competition of stereospecific E2 elimination versus SN2 substitution is of central importance in chemical synthesis.Herein,we uncover how the nature of the leaving group affects the intrinsic competing dynamics that remains largely unknown as opposed to its role in reactivity.Results are presented for a prototype case of fluoride anion reacting with ethyl chloride,compared to reacting with ethyl iodide.Chemical dynamics simulations reproduce scattering signatures observed in experiments and reveal that the direct stripping/rebound mechanisms characterize the E2/S_(N)2 reactions,in line with their dynamic fingerprints identified.Quite similar structures and energetics are found for the Cl^(−)and I^(−)leaving halides,whereas the competing dynamics show markedly distinct features.A halogen-bonding attraction is found to be crucial that modifies the interaction potential in the entrance channel and essentially tunes the underlying atomistic behaviors causing a mechanistic shift.This work highlights the dynamical effects induced by a leaving group on the proceedings of baseinduced elimination and nucleophilic substitution,providing a unique insight into the reaction selectivity for complex chemical networks and environments.展开更多
The mechanism for the decomposition of 2-mercaptoethyl O-ester was theoretically investigated.The mecha-nism that 2-mercaptoethyl O-ester undergoes an S_(N)2 displacement of the O atom by the S atom onα-C is much fa-...The mechanism for the decomposition of 2-mercaptoethyl O-ester was theoretically investigated.The mecha-nism that 2-mercaptoethyl O-ester undergoes an S_(N)2 displacement of the O atom by the S atom onα-C is much fa-vored over the mechanism of N-to-S acyl transfer.The length of the alcohol moiety has large effects on the decom-position efficiency of thiol-substituted alkyl O-esters.The reactivities of these esters are controlled by distortion en-ergies.Only 2-mercaptoethyl O-ester can undergo the decomposition at room temperature due to the low distortion energy to achieve the transition state geometry.If the thiol group of 2-mercaptoethyl O-ester is replaced by an amino group,the N-to-N acyl transfer mechanism is more favored than the S_(N)2 displacement mechanism.展开更多
基金Financial support from National Key R&D Program of China(2022YFA1503200)National Natural Science Foundation of China(Grant No.22371149,22188101)+2 种基金the Fundamental Research Funds for the Central Universities(No.63223015)Frontiers Science Center for New Organic Matter,Nankai University(Grant No.63181206)Nankai University are gratefully acknowledged.
文摘Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highly valuable ester derivatives were obtained in a direct and rapid way.This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance,using cheap and abundant electrodes and completed within a short reaction time.Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology.The mechanistic investigations and density functional theory(DFT)calculations verified the feasibility of the proposed pathway of this transformation.
基金supported by the State Key Lab of Urban Water Resource and Environment of Harbin Institute of Technology(No.ES202303)the National Natural Science Foundation of China(No.22203039).
文摘The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation.Considering the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision energies.Remarkably,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain elimination.Chemical dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing processes.Interestingly,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism shift.These features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.
基金supported by the State Key Lab of Urban Water Resource and Environment of the Harbin Institute of Technology(No.ES202303)。
文摘Ubiquitous competition of stereospecific E2 elimination versus SN2 substitution is of central importance in chemical synthesis.Herein,we uncover how the nature of the leaving group affects the intrinsic competing dynamics that remains largely unknown as opposed to its role in reactivity.Results are presented for a prototype case of fluoride anion reacting with ethyl chloride,compared to reacting with ethyl iodide.Chemical dynamics simulations reproduce scattering signatures observed in experiments and reveal that the direct stripping/rebound mechanisms characterize the E2/S_(N)2 reactions,in line with their dynamic fingerprints identified.Quite similar structures and energetics are found for the Cl^(−)and I^(−)leaving halides,whereas the competing dynamics show markedly distinct features.A halogen-bonding attraction is found to be crucial that modifies the interaction potential in the entrance channel and essentially tunes the underlying atomistic behaviors causing a mechanistic shift.This work highlights the dynamical effects induced by a leaving group on the proceedings of baseinduced elimination and nucleophilic substitution,providing a unique insight into the reaction selectivity for complex chemical networks and environments.
基金We thank the National Natural Science Foundation of China(No.21202102)for the financial support.
文摘The mechanism for the decomposition of 2-mercaptoethyl O-ester was theoretically investigated.The mecha-nism that 2-mercaptoethyl O-ester undergoes an S_(N)2 displacement of the O atom by the S atom onα-C is much fa-vored over the mechanism of N-to-S acyl transfer.The length of the alcohol moiety has large effects on the decom-position efficiency of thiol-substituted alkyl O-esters.The reactivities of these esters are controlled by distortion en-ergies.Only 2-mercaptoethyl O-ester can undergo the decomposition at room temperature due to the low distortion energy to achieve the transition state geometry.If the thiol group of 2-mercaptoethyl O-ester is replaced by an amino group,the N-to-N acyl transfer mechanism is more favored than the S_(N)2 displacement mechanism.
